Darehk the Quick is a Sunspearghost who eternally walks the first city, Fahranur, guarding Elona from an unknown evil. Because of this, he holds a tablet that the player needs to acquire in order to access the next area of the mission Jokanur Diggings. Ordinarily, Darehk is just annoying, however, in Hard Mode, his Healing Signet heals for a great deal of health, and he has a non-removable, permanent 33% speed boost. A snare will be necessary. Imagined Burden, even with few or no points in Illusion Magic, will usually suffice.
When not too close, a Longbow or Flatbow can hit him without triggering his movement. It's a good idea to bring an interrupt to prevent his Healing Signet in Hard Mode.